Portable air driven chain saw



y 1961 A. G. LEDGER 2,990,858

PORTABLE AIR DRIVEN CHAIN SAW Filed May 2'7, 1959 United States Patent2,990,858 PORTABLE AIR DRIVEN CHAIN SAW Anderson G. Ledger, P.0. Box853, Terra Bella, Calif. Filed May 27, 1959, Ser. No. 816,315 2 Claims.(Cl. 14332) This invention relates to saws and more particularly to anair driven portable chain saw.

It is an object of the present invention to provide a portable chain sawthat can be conveniently used in all types of terrain, and which can beenergized by pneumatic pressure, in the absence of a source ofelectrical energy.

Another object of the present invention is to provide a light weight,and easy to handle portable chain saw employing pneumatic pressure toeffect operation thereof and which can be readily handled with a minimumof effort.

Other objects of the invention are to provide a portable air saw bearingthe above objects in mind which is of simple construction, has a minimumnumber of parts, is inexpensive to manufacture and eflicient inoperation.

For other objects and for a better understanding of the invention,reference may be had to the following detailed description taken inconjunction with the accompanying drawing, in which:

FIGURE 1 is a side elevational view, with parts broken away, of aportable air saw made in accordance with the present invention;

FIGURE 2 is a rear elevational view of the saw shown in FIGURE 1;

FIGURE 3 is an enlarged longitudinal cross sectional view of a pneumaticresponsive valve mechanism for controlling operation of the saw; and

FIGURE 4 is a perspective view of this invention embodying a circularsaw.

Referring now more in detail to the drawing, a portable air saw made inaccordance with the present invention is shown to include a housing 12having a handle 14 at one end into which a flexible air hose 16 extends.The innermost end of the air hose 16 is connected by means extendingthrough said handle to a valve housing 18 having an outlet 20 that is incommunication with an air motor of any desired conventionalconstruction. Said air motor carrying and operating a chain sprocketmounted thereon (not shown). A poppet valve member 24 is movable betweena normally closed seated position upon an intermediate valve seat 22arranged at an angle with the horizontal and an open position inresponse to an axial force directed upon the stem 26 of the valve member24. Said stem 26 arranged at an angle with the horizontal and with itsfree end outside the path of travel of the forced air from the hose.(See FIG. 1.) However, a relatively strong compression coil spring 28acting between a trigger mechanism 30 and the valve housing 18 normallymaintains the valve 24 in seated engagement with the valve seat 22. Thecoil spring 28 is arranged within the hollow handle, free from contactwith air under pressure. The actuating trigger 30 having an upper armand a lower arm and is pivotally carried intermediate its ends withinthe handle 14 upon a transversely extending pivot pin 32, and having atransverse bore in the free end of its upper arm.

The conventional air motor also mounted within the front end of thehousing 12 is drivingly connected to the endless saw chain 38 that isguided along both sides of a cutting bar 34 by means of a guide pulley33 and sprocket on said air motor. Thus, in response to actuation of theair motor by high pressure air passing through the line '1-6 in responseto actuation of the trigger 30, the air motor is effective to drive thesaw chain 38. A C-shaped handle 36 may be readily mounted on either sideof the housing 12 intermediate its ends, to enable such saw to be usedby either a right handed or a left handed person.

As shown by FIG. 4, the air motor is mounted in housing 12' and drivescircular blade 38' by suitable means, and embodying trigger 30. Air hose16' is shown attached to housing.

It will now be recognized that it is only necessary to provide a smallair compressor for supplying suflicient pressure to operate the saw.Such air compressor may be conveniently driven by a small gasolineengine, in any location, and without any need for electrical energy.

While various changes may be made in the detail construction, it shallbe understood that such changes shall be within the spirit and scope ofthe present invention as defined by the appended claims.

What I claim as new and desire to protect by Letters Patent of theUnited States is:

1. A portable pneumatically operated chain saw comprising, alongitudinal horizontally extending hollow cylindrical housing with anintegral hollow handle extending downwardly and outwardly from the rearend thereof, a saw chain supporting bar secured to and extendingforwardly of said cylindrical housing, a C-shaped handle mounted uponthe side wall of said cylindrical housing intermediate its ends, a guidepulley rotatably mounted on the outer end of said chain supporting bar,an air motor mounted within the forward end of said cylindrical housing,a sprocket carried by said motor, an endless saw chain mounted aboutsaid pulley and said sprocket and traveling along both sides of saidsupport bar, said air motor thereby effecting the movement of said sawchain, a valve housing arranged within said cylindrical housing in anangular position, said valve housing having an inlet and an outlet, anair hose connected with said inlet in said valve housing, a poppet valveseat arranged angularly within said valve housing, an aperture in thewall of said valve housing adjacent said hollow handle, a poppet valvearranged in said valve housing with its stem extending downwardly andrearwardly with its free end portion extending through said aperture andinto said hollow handle, a bell crank type trigger pivotally mountedbetween its ends within said hollow handle and with its lower armnormally depending vertically outside the handle and its upper armextending at right angles from said lower arm and having its outer freeend secured to the free end of said valve stem, an air passage extendingfrom said air inlet to said valve seat in said valve housing, a coilspring sleeved upon the free end portion of the valve stem extendingoutside said valve housing and free from contact with forced air passingthrough said passageway, the upper surface of said poppet valve beingfree from contact with any moving parts, and a passage for conveyingforced air from said valve seat through said outlet to said motor, andair means connected with said air hose for actuating said motor whensaid air valve is actuated by movement of said trigger.

2. A portable pneumatically operated chain saw comprising, alongitudinally extending hollow cylindrical housing, a chain supportingbar secured to and extending outwardly in axial alignment with and fromsaid cylindrical housing, a chain guide pulley carried by the end ofsaid bar remote from said cylindrical housing, a downwardly andrearwardly extending hollow handle of the pistol grip type integrallyformed with the rear end portion of said cylindrical housing forming acoil spring housing chamber free from air under high pressure, a bellcrank type trigger pivotally mounted between its ends within the pistolgrip handle and with its lower arm normally depending vertically outsidethe handle and its upper offset arm extending substantially at rightangles from said lower arm and having a transverse bore in its free endportion and arranged Within said pistol grip handle, a conventional airmotor mounted within the forward end of said cylindrical housing, achain sprocket carried by said air motor, a valve housing angularlymounted within the rearward end of said cylindrical housing, saidhousing having an inlet at its rear upper end portion and an outlet inits forward lower end portion, tubular means connecting said' outlet inthe lower end portion of said angular'ly arranged valve housing withsaid air motor, an air hose connected with said inlet means in saidupper end portion of said valve housing, a valve port with a valve seatintermediate said inlet and said outlet of said valve housing, a poppetvalve with a valve head and an integral angularly extending valve stem,said valve stem having a depending free end, said valve head normallyclosing said valve port with its top surface free from contact with anyworking parts, a bore in the bottom wall of said valve housing, saidfree end of said valve stem extending through said bore dependingexternally of said valve housing and free from contact with the airunder pressure from said hose, said valve stem arranged in axialalignment with said pistol grip and at right angles to said offset upperarm of said trigger and having its free end connected by suitable meansextending through said transverse bore in the free end of said upper armof said trigger, a coil spring mounted upon the free end portion of saidvalve stem and arranged between the exterior surface of said valvehousing and said upper arm of said trigger normally maintaining saidvalve head in seated engagement with said valve seat, said coil springfree from contact with the air under pressure from said hose wherebyactuation of said trigger causes inward and upward movement of saidvalve stem and effecting opening of said valve port, whereby the airunder pressure passes the intermediate portion of said valve stem andthen past the valve seat and the underside of said valve, a chain sawtrained about said guide pulley and said sprocket and traveling alongboth sides of said chain supporting bar, and air means connected withsaid air hose for actuating said motor when said air valve is actuatedby said trigger.

References Cited in the file of this patent UNITED STATES PATENTS1,260,702 Olson Mar. 26, 1918 2,351,740 Blurn June 20, 1944 2,649,871Desbarat Aug. 25, 1953 FOREIGN PATENTS 656,811 Germany Feb. 15, 1938

